Process timer



NOV. 22, 1949 c, MARBLE 2,489,098

PROCESS TIMER Filed Feb. 23, 1946 Fig.1.

Inventor: Chester 8. Marble,

His Attorney.

Patented Nov. 22, 1949 UNITED STATES PATENT OFFKIE PROCESS TIMER Chester B. Marble, Ashland, Mass, assignor to Telechron Inc., a corporation of Maine Application February 23, 1946, Serial No. 649,590

4 Claims. 1

My invention relates to an interval timer for timing processes such, for example, as photograph printing time, and its object is to provide a. simple, reliable, electrically driven timer, adjustable as to the process time, and in which the circuit of the driving motor and the circuit of the process timer are made and broken simultaneously such that the driving motor is energized only during a process timing operation. In carrying my invention into effect, the field of the timing motor is employed as a relay which will hold a normally open switch closed when the motor is energized. Closing of this switch energizes the motor and starts a process timing operation. At the end of the timing interval this switch or another switch in series relation with the motor is opened, thereby stopping the motor and allowing the relay switch to open. Fig. 1 shows the two-stretch arrangement and Fig. 2 the single-switch arrangement.

Referring to the drawing, Fig. 1, the process circuit to be controlled is represented as containing an incandescent lamp I supplied from an alternating current source 2. For convenience in using the lamp at times when a timing operation is not called for, the lamp may be connected to the source of supply by a double-throw manual switch 3 when moved to contact 4. When the lamp or other process circuit is to be time-controlled, the switch 4 is moved to a contact 5 so as to connect the lamp to the source of supply 2 through the process timer represented at the right in the drawing.

The timer is driven by a self-starting synchronous motor having a field winding 6, and a magnetic field core 1 containing a shaded pole rotor gap at 8 into which gap there is inserted the reduced end portion of a rotor and gear casing 9. Within this casing there are a suitable rotor for the motor rotatively mounted in the gap 8 of the field core and suitable reduction gearing with sealed-in lubrication. The terminal or low speed end of the gearing is connected to drive a shaft Ill extending through a bushing in the larger end of the gear casing. In the example to be de scribed it will be assumed that the shaft In is driven at the rate of one revolution per minute in a counterclockwise direction by the motor when the motor is in operation. As thus far described, the motor in question may be similar to the timer motor unit described in United States Patent No. 1,495,936May 27, 1924.

For the purposes of my invention the motor core has core parts ll extending from the coil section away from the gap 8 and forming with a from contact It for convenience in obtaining the proper adjustment during assembly. At least one of the relay pole pieces is preferably provided with a shading coil I9 to reduce chatter of the armature core when energized With alternating flux from the motor magnetic circuit. The armature may be provided with a button 20 for convenience in pushing it to a closed position. In the energized position of the armature the magnetic circuit formed thereby which is in shunt to the motor flux circuit does not necessarily need to be fully closed, and in any event, may be so designed in relation to the field coil as to accomplish the intended purpose without shunting the motor operating magnetic circuit flux to a point when the motor is unreliable in operation.

My improved timer includes another switch formed by contacts 2| and 22 normally biased to a closed position by the resiliency of contact member 22 but held in an open position as shown by a cam projection 23 at one point on the periphery of a disk 24 which disk is connected in driving relation with the timer shaft l0 through a friction clutch consisting of the disk 24 and a disk 25 secured to shaft ill with a saucer-shaped spring 26 compressed between such disks. The shaft It] extends forward through the center of the friction clutch parts as shown. Disk 24 has a hollow shaft extension 21 rotatively mounted on shaft 40 and secured thereon by a screw 28. A knob 29 having a. pointer 33 is secured to the hollow shaft extension 21 by a setscrew 32. The pointer 30 indicates on a stationary time scale 3| which in the example given is graduated in seconds from 0 to 60, reading in a clockwise direction or in the direction opposite to that in which the pointer 30 will be driven by the motor.

The motor field coil 6 is connected in series relation through the two switches described across the source of supply 2, and for a process timing operation the lamp I is likewise generally connected in series relation through the two switches described across the source of supply when both of such switches are closed. The switch formed by contacts 2| and 22 is open only when the aseaoos pointer II is in the zero indicating position on scale IL since only at this time does the cam hump or tooth 2! on disk 24 hold these contacts open.

The switch formed by contacts II and i1 is normally open. It may be closed manually by pushing down on button ll. When pressure is removed, this switch will remain closed only it the motor is energized.

Starting with the apparatus in the normal, inactive condition represented in the drawing, it is used as follows: The unit consisting of knob Il, pointer I0, and cam disk 24 is turned from the zero time position shown until the pointer 80 indicates the number seconds desired for a process timing period. The knob may be turned in either direction for this purpose. For instance, it the period is to be seconds, pointer is ordinarily would be turned clockwise and if 55 seconds, the pointer ll ordinarily would be turned counterclockwise, or the shortest distance to indicate on dial II the number oi seconds or other time units in the desired timing interval period. In this operation the friction clutch at 28 slips. Such setting operations close the switch comprising contacts 2i and 22. The circuits of lamp l and motor coil I are 01' course open at contacts II and I1, so that nothing else happens as a result 0! this time setting operation.

To start the timing operation, the armature i2 is closed as by pushing down on knob 1.. This closes contacts II and i1 and completes the circuit of both the motor coil 6 and lamp I. Because the motor field is now energized, the armature l2 remains energized and its switch closed after pressure on knob 20 is removed. The motor starts instantaneously and drives the pointer ill and its connected disk 2| counterclockwise tow'ardthe zero time position on scale 3| at a constant rate 01' speed; and at the end of the time interval the pointer reaches the zero position, contacts 2| and I! are opened by cam lobe 2!, the motor and lamp are deenerglzed, the motor stops and armature i2, being no longer attracted, moves to the deenergized position,

essential; nor is it essential that the normally closed switch comprising contacts 2| and 22 be included in the process circuit controlled by the timer. Where remote control starting is desired, the relay apparatus may be so designed as to close contacts I and II as well as to keep them closed when the motor coil is energized. For this purpose a normally open push button switch 34 may be momentarily closed and thus used in place of button II to start a timing operation.

If desired, the two switch means of Fig. 1 may be combined in a single switch means as represented in Fig. 2, where the armature i2 is shown as provided with an arm 35 extending from its free end to the vicinity of resilient contact member Zla such that when the armature is pushed down to energized position, the arm 35 pushes contact member 2ia down where it will make contact with contact member 22 only when the latter is in the raised position shown. The parts are shown in the position they will assume following a time setting operation but before the armature I2 is pushed down to energized position. At the end of a process timing operation the switch is opened by hump 23 pushing down on contact member 22. The operation is otherwise the same as in Fig. 1.

The periphery of the disk 25 may be provided with evenly spaced ratchet teeth It to oscillate a resilient member 31 for the purpose of making an audible click at spaced time intervals. For

- instanc, where the disk 25 is driven at the rate opening the contacts II and I1 and thus preventing any further energization of the load circuit due to arcing, etc., across the small gap openings at contacts 2| and 22 or by resumption oi! contact at these contacts. The apparatus is now ready for another process timing operation such as just described.

Additonal circuits or signal devices such as represented at 31 may be connected in parallel with lamp I. The armature I! when energized may easily be designed to give a slight buzzing sound it that is desired, so as to act as an audible signal to indicate to a person near the same when a processing timing operation is completed without looking at or being able to observe the pointer 3|.

In case the motor terminal shalt ll operates clockwise, the dial it would be graduated in the counterclockwise direction. The terminal shalt ll may of course be geared to operate at any desired speed such, for example, as one revolution per hour in which case the dial II would have a -minute graduation instead of being graduated in seconds. It is oi course relatively immaterial whether the graduated scale part or the pointer part of the time indicating system he made rotatable.

While the process circuit which is controlled by the timer has been shown as being energisedirom the same source as the motor, this is not of one revolution per minute, the disk could have 60 teeth so that during a timing operation the member 31 would produce an audible click at one-second intervals or "tick of! seconds. The member 31 is resilient and its free end is biased against the periphery of disk 25, and is so arranged in relation to the shape of the ratchet teeth as to snap over the teeth as the disk rotates as to make an audible click. This is of value during a photographic printing exposure in a dark room where the operator desires to shade a portion of the image for a part of the total timed interval. The member 31 may be lifted from the disk 25 during a setting operation or when the audible click is not desired.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A timer comprising a constant speed electric motor having a magnetic field core with a motor armature gap and a relay armature gap in parallel magnetic relation, and energizing coil on said field core for producing operating flux across both gaps, a magnetic relay armature pivoted on said core adjacent the relay gap and biased to detracted position, said relay parts being adjusted such that the armature will be held in attracted position when the motor coil is energized, a switch closed by said rela armature only when in at-- tracted position, a motor armature in the motor armature gap, time indicating parts including a time graduated scale and a pointer cooperating with said scale one of which is stationary and the other of which is rotatively mounted and adapted to be driven by said motor but which is rotatively adjustable relative to said motor for time setting purposes, a normally closed switch adapted to be opened by said rotary part only when said time indicating parts indicate zero on the time scale, said two switches being connected in series circuit relation with said energizing coil.

- 2. A timer comprising a self-starting synchronous motor, a time graduate scale, a pointer indicating on said scale and adapted to be driven by agoo:

said motor in a down scale direction, means whereby said pointer may be manually rotatively adjusted relative to the motor for Setting the pointer to any desired time graduation mark on said scale, a normally closed switch in series relation with said motor, means moved with said pointer for opening said switch only when the pointer is in a zero time indicating position relative to said scale, a normally open switch also in series relation with said motor, means for manuall closing said normally open switch when the pointer has been set away from a zero time indicating position relative to the scale thereby starting a timing operation, and means operated by flux from the motor to maintain the normally open switch closed only when the motor is energized, and a circuit to be time connected though said normally open switch.

3. A time comprising a constant speed electric motor having a magnetic core with a motor armature gap and a relay armature gap in parallel relation, an energizing coil on said field core for producing operating flux across both gaps, a magnetic relayarmature pivoted on said core adjacent the relay gap and biased to detracted position, said relay parts being adjusted such that the armature will be held in attracted position when the motor coil is energized, a motor armature in the motor armature gap, time indicating parts including a time graduated scale and a pointer cooperating with said scale, one of which is stationary and the other of which is rotatively mounted and adapted to be driven by said motor but which is rotatively adjustable relative to said motor for time setting purposes, an energizing circuit for said motor and switching means in said circuit associated with said relay armature and said motor driven time indicating part such that the motor energizing circuit is closed only when the armature is in attracted position and the time indicating parts indicate other than zero on the time indicating scale.

4. A timer comprising a self-starting synchronous motor, a time graduated scale, a pointer indicating on said scale and adapted to be driven by said motor, means whereby said pointer may be manually rotatively adjusted relative to said motor for setting the pointer to any desired time graduation mark on the scale, a relay armature member associated with the field of said motor normally biased to a detracted position but capable of being held in an attracted position when the motor is energized, and switching means including a contact moved by said armature and a contact moved with said pointer when the latter moves to and from a zero time indicating Position said contacts being in series relation in the energizing circuit of said motor, said contacts closing the motor circuit only when the pointer is in other than a zero time indicating position and said armature is in attracted .position.

CHESTER B. MARBLE.

REFERENCES CITED The following references are of record in the Certificate of Correction Patent No. 2,489,098

November 22, 1949 CHESTER B. MARBLE It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 2, line 26, for the word "when read where; column 4, line 53, for and read an; column 5, line 17, for time read tuned;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the ease in the Patent Oflice.

Signed and sealed this 25th day of April, A. D. 1950.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

